1. Field of the Invention
The present invention relates to a solar cell array and an electronic equipment having the solar cell array, and more particularly to a solar cell array capable of converting an input light such as sun light or artificial light to electricity and an electronic equipment such as a camera or a calculator having the solar cell array.
2. Related Background Art
A conventional solar cell array has a circuit configuration of a plurality of serially connected cell groups each having a plurality of parallelly connected unit cells. The solar cell array of such a circuit configuration has a planar arrangement of unit cells wherein the parallelly connected unit cells are arranged in rows (or columns) and the serially connected unit cells are arranged in columns (or rows).
For example, as shown in the circuit diagram of FIG. 1, two unit cells 1-A and 1-C, and two unit cells 1-B and 1-D are respectively connected in parallel to form parallel circuits 11 and 12, and the two parallel circuits 11 and 12 are connected in series to form a two-terminal solar cell array 1. Namely, as shown in the arrangement diagram of FIG. 2, the unit cells 1-A and 1-C and the unit cells 1-B and 1-D are respectively arranged in rows, and the unit cells 1-A and 1-B and the unit cells 1-C and 1-D are respectively arranged in columns to form a solar cell array 1a. Thus, in the prior art, the individual unit cells shown in FIG. 1 are usually arranged such that the parallelly connected unit cells are arranged in the same row (or column) and the serially connected unit cells are arranged in the same column (or row).
Similarly, as shown in the circuit diagram of FIG. 3, in a solar cell array 2 having pairs of unit cells 2-A and 2-D, 2-B and 2-E, and 2-C and 2-F connected in parallel and the three parallel circuits 21, 22, and 23 connected in series, the parallelly connected unit cells 2-A and 2-D, 2-B and 2-E, and 2-C and 2-F are arranged in respective rows (or columns), and the serially connected unit cells 2-A, 2-B and 2-C and 2-D, 2-E and 2-F are arranged in respective columns (or rows) to form a solar cell array 2a, as shown in the arrangement diagram of FIG. 4. As shown in FIGS. 5 and 6, in a three-row-by-three-column (3.times.3) solar cell array 3, the parallelly connected unit cells are arranged in respective rows (or columns) and the serially connected unit cells are arranged in respective columns (or rows) to form a solar cell array 3a.
However, in the solar cell array of the above arrangement, problems of shading of the solar cell array or the impediment of the incident light to a portion of the solar cell array are encountered.
The shaded area is formed on the side opposite to a light source and it is projected onto the solar cell array to reduce the illumination light intensity on the incident plane of the solar cell.
The shaded area is frequently formed to extend longitudinally or laterally. In the prior art described above, when a row or column of the solar cell array is shaded so that the power generation ability of the unit cells of that row or column is drastically reduced, the overall current generated by the solar cell array drastically decreases. This effect is explained below.
For example, in FIGS. 1 and 2, when a row of solar cells is shaded so as to reduce the power generation ability of, e.g., the unit cells 1-A and 1-C, the unit cells 1-A and 1-C are placed in an off state and the overall current generated by the solar cell array 1a may decrease to a small value on the order of the leakage currents of the cells 1-A and 1-C.
Similarly, in FIGS. 3 and 4, when a row of solar cells is shaded so as to drastically reduce the power generation ability of, e.g., the unit cells 2-A and 2-D, the overall current generated by the solar cell array 2a may decrease to a small amount on the order of the leakage currents of the unit cells 2-A and 2-D.
Similarly, in FIGS. 5 and 6, when a row of solar cells is shaded so as to drastically reduce the power generation ability of, e.g., the unit cells 3-A, 3-D, and 3-G, the overall current generated by the solar cell array 3a may decrease to a small amount on the order of the leakage currents of the unit cells 3-A, 3-D, and 3-G.